On 6/11/19 7:59 AM, Matthew Beliveau wrote:
Hello,
Correct me if I'm wrong, but before the function checks for virtual
bases, an if-statement checks for extra_warnings on line 6049(when my
patch is applied). The check was there before I made my changes, and
my test fails
without -Wextra. Below is the code above the warning call:
if (extra_warnings)
for (vbases = CLASSTYPE_VBASECLASSES (t), i = 0;
vec_safe_iterate (vbases, i, &binfo); i++)
{
basetype = BINFO_TYPE (binfo);
Just as an FYI, testing warning flags prevents #pragma GCC
diagnostic from having the expected effect:
struct A { };
struct B : virtual A { };
struct C : A { };
struct D0 : B, C { }; // -Winaccessible-base (good)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wextra"
struct D1 : B, C { }; // -Winaccessible-base not suppressed
#pragma GCC diagnostic pop
struct D2 : B, C { }; // -Winaccessible-base (good)
(A more realistic use case is supressing -Wextra before including
a third party header and then restoring it.)
This can be solved by adding a function (say, is_warning_enabled
(int)) that does the same #pragma-sensitive checking as warning()
and calling it instead of testing extra_warnings directly. I.e.,
if (is_diagnostic_enabled (OPT_Wextra))
...
warning (OPT_Winaccessible_base, ...);
Martin
Unless I'm mistaken and you meant for me to check for extra_warnings
again in the if-statement directly above the warning call.
Thank you,
Matthew Beliveau
On Tue, Jun 11, 2019 at 12:43 AM Jason Merrill <ja...@redhat.com> wrote:
On 6/10/19 12:02 PM, Matthew Beliveau wrote:
if (!uniquely_derived_from_p (basetype, t))
- warning (OPT_Wextra, "virtual base %qT inaccessible in %qT due "
- "to ambiguity", basetype, t);
+ warning (OPT_Winaccessible_base, "virtual base %qT inaccessible in "
+ "%qT due to ambiguity", basetype, t);
You mentioned using -Wextra for this message, and you have a testcase
for it, but here you remove the only connection between this message and
-Wextra: with this patch, the virtual base warning will be enabled by
default. Perhaps you want to check extra_warnings in the if condition?
Jason
